Arrangement for controlling deposition of plating baths

ABSTRACT

An arrangement for controlling the deposition state in plating baths. The baths are equipped with fully automatic plating installation, material dispatching centers, transport arrangements, and drop-off locations. A central control unit has its circuit elements logically interconnected with circuit elements in the transport arrangement and the drop-off locations. Storage devices in the central control unit store the deposition information of each location .

Sept. 25, 1973 KARL-HEINZ STRUM 3,761,378

ARRANGEMENT FOR CONTROLLING DEPOSITION OF PLATING BATHS Filed June 22, 1971 5 Sheets-Sheet z SET 7 CLEAR START FROG AMMA BL E [j DIODE C ON/VE C T/ONS PROGRAMMABLE W/RE CONNECT/0N3 F l F F F F soy or 60V or Lu 60V or 60V 0V u k 3 m w a n Q Q R Q 5 5 *"Q5 5 g R k 3 h "3 i 5 v Q m, i5 E E Q Q q *6 QB m INVENTOR.

KARL HE/NZ STURM BY Fig.2 6' E A 7'TORNE Y P 1973 KARL-HEINZ STRUM 3,761,378

ARRANGEMENT FOR CONTROLLING DEPOSITION OF PLATING BATHS Filed June 22, 1971 5 Sheets-Sheet 4 DEPOS/T/0N CARR/AGE ACTUATES FT4 SWITCH NUMBER RA lS/NG LOWER/N6 6 TORAGE 5 TORAGE HSP 5 SP 55 T SET IN VEN TOR.

KAR L. HE/NZ STURM rwm ATTORNE Y United States Patent O 3,761,378 ARRANGEMENT FOR CONTROLLING DEPOSITION OF PLATING BATHS Karl-Heinz Sturm, Feucht, Germany, assignor to Schering AG, Berlin, Germany Filed June 22, 1971, Ser. No. 155,457 Int. Cl. B01k 3/00; C23]: 5/68 US. Cl. 204202 7 Claims ABSTRACT OF THE DISCLOSURE An arrangement for controlling the deposition state in plating baths. The baths are equipped with fully automatic plating installations, material dispatching centers, transport arrangements, and drop-off locations. A central control unit has its circuit elements logically interconnected with circuit elements in the transport arrangement and the drop-off locations. Storage devices in the central control unit store the deposition information of each location.

BACKGROUND OF THE INVENTION The present invention relates to a circuit arrangement for controlling the deposition state of plating baths equipped with fully automatic plating installations, material dispatching center, transport arrangements and dropoff locations.

In a conventional method for controlling the deposition state of plating baths, the material carrier actuates electrical or magnetic switches during the dropping-off process. The deposition state of the baths is thereby transmitted by cable to the central control arrangement.

A disadvantage of this invention method is that the circuit elements actuated by the electrical or magnetic switches must be provided on all material carriers and must ride with these. As a result, considerable mechanical and chemical problems prevail. In addition, it is disadvantageous that electrical or magnetic switches must be provided at each drop-off or deposition location and at each plating bath whose deposition state is to be monitored. A considerable amount of installation equipment is required for installing such electrical or magnetic switches. Furthermore, careful adjustments are required since the circuit elements of each individual material carrier is to actuate the associated electrical or magnetic switches in sequence at all deposition locations or pltaing baths.

In view of the large number of switching contacts which must be interconnected with a large number of material carriers, the adjustments introduce diificulties to the extent that errors arise in controlling the deposition state.

In another conventional method, the deposition of a bath is monitored by providing a mechanical, optical, or inductive sensor on the transport carriage itself. The sensor becomes actuated when the transport carriage is located over a bath. In such an arrangement, similar disadvantages prevail. Thus, the sensor must be interconnected with all material carriers, and therefore it must be interconnected with the cams, actuators, or similar such devices intermittently for this purpose.

Since the material carrier can be removed in part from the arrangement, the possibility exists that there be no longer correspondence between the sensor and the element sensed, so that erroneous indications occur. It is a disadvantage therefore, that deposition monitoring is then only possible when the transport carriage passes the applicable bath or deposition location.

Consequently, for all other bath locations or deposition stations which are not serviced by a carriage, it is not possible to transmit information concerning the deposition state.

In both of the preceding methods another disadvantage is present, in that all deposition signals are initiated by the 3,761,378 Patented Sept. 25, 1973 material carriers themselves. As a result, the movement of the carriers cannot be simulated.

It has been found in practical applications, that the movement of the carriers need not be traced in actual form, but essentially only simulated, during the incoming or outgoing phase or in transferring from one program to another program.

Similarly, it is advantageous to simulate the movement of individual material carriers when the individual carriers or drum carriers must be removed for predetermined reasons as for example, waiting delays, repairs, or the like.

Accordingly, it is an object of the present invention to avoid the aforementioned disadvantages, and to monitor the deposition state of all baths and deposition stations. It is the object of the present invention to carry out these functions without the installation of electrical or magnetic switches at these baths or deposition stations. It is also an object of the present invention that all material carriers are not to be required to be active.

The objects of the present invention are achieved by providing a circuit arrangement with a central control unit in which the circuit elements are logically interconnected with elements in the transport arrangement and the deposition stations. The arrangement is such that the deposition information of each station is stored in a storage device contained in the central control unit. These stations correspond to the deposition or drop-off locations or plating baths.

SUMMARY OF THE INVENTION A circuit arrangement for controlling the deposition state in plating baths. The baths are equipped with fully automatic plating devices, material dispatching stations, transport carriages, deposition stations, and logical circuit elements therein. A central control unit has logic circuit elements interconnected with those in the transport carriage and the deposition stations. Storage devices in the central control unit store deposition information of each deposition station.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1 to 3 are circuit diagrams of the control arrangement for controlling the deposition in plating baths, in accordance with the present invention;

FIG. 4 is an operational flow diagram of the circuits of FIGS. 1 to 3;

FIG. 5 is a schematic diagram of a plating arrangement, in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The transport operations consist of forward, reverse, raising and lowering processes of the transport equipment in the form of the transport carriage or Wagon. These are equipped with two drives: one drive is for forward and reverse, and one drive is for raising and lowering of the material carrier, so that these can be deposited in the plating positions as for example, the plating tanks.

In conjunction with the arrangement shown in the drawing, is a deposition storage, BSP with a corresponding number of storage positions. Furthermore, there is provided a lowering storage SSP and a raising storage HSP. These storage units may be in the form of relay memory devices or electronic storage circuits.

Positional switches ST are arranged in conjunction with the transport equipment or the transport carriage. These switches are preferably provided in separate planes so that g plurality of inputs A, B One input is provided for each transport carriage whose region of motion encompasses the corresponding stationary position.

The progressive numbering of the positional switches ST is identical with the corresponding numbering of the deposition storage BSP. For the deposition storage, the sequential character identifies the input to the storage. Thus, the first input is denoted by A, whereas the second input is denoted by B, etc. All of these inputs are equally and freely determined.

Each transport carriage is furthermore, provided with a lowering storage SSP and a raising storage HSP. These hold the directions'of the raising or lowering motion until the time that the carriage leaves the corresponding stationary location.

The commands or instructions for driving forward FV, reverse FR, raising H, and lowering S are generated in a unique manner in order to facilitate the storage step or the information transmission.

The operation of the arrangement may be described in conjunction with an example, in accordance with the present invention.

A transport carriage consisting of a raising beam with motor and a lifting motor, brings a material carrier in raised position to the fourth tank or bath of a row of baths, ST4, and remains at that position. The raising mechanism then lowers the material carrier into the bath. After termination of the lowering motion, the transport carriage leaves the bath in forward direction with lowered raising mechanism, while the material carrier remains in this bath.

In this case, the deposition takes place in a bath that was vacant until now. The deposition signalling occurs in the following manner: The moving carriage actuates the positional switch ST4 after attaining the bath 4. The lowering process clears an information memory in the lowering storage SSP. After this lowering, the deposition state information is transmitted onto the deposition storage BSP, through the signal for driving on with lowered raising mechanism and reading out the lowering storage SSP and the positional switch ST4.

This information remains in the deposition storage BSP4 until the material carrier is again lifted out of this bath.

This process is carried out as follows: The transport carriage arrives with lowered raising mechanism at bath 4 and remains there. The raising mechanism then lifts the material carrier out of the bath, and actuates thereby the raising storage HSP. After reaching the uppermost position and after termination of drippage, the carriage leaves this position, and the driving signal in conjunction with the raising storage and the positional switch ST4 clears the information in the deposition storage, which designates that the bath is in use.

The switching arrangement may be described in conjunction with FIGS. 1 to 3 which show the bath deposition.

When a transport carriage arrives at a bath, the corresponding positional switch ST becomes actuated as, for example, .ST2. Through actuation of the positional switch, the associated deposition storage BSP, as for example BSPZ, becomes opened. In this manner the set and clear signals can "be transmitted.

When the transport carriage now carries out a lowering or raising motion, this becomes applied to the lowering storage SSP or in the raising storage HSP.

After the transport carriage has terminated its raising motion, and it has left the bath in lowered or raised state, the clear or set signal is transmitted to the deposition storage, over the lowering or lifting contact, and is there stored. The carriage may leave the bath under either one of the states of forward or down reverse, or up forward or up reverse.

Before the transport carriage leaves entirely the positional switch, the lowering and raising storage is set or reset to 0 by a switch on the carriage. This switch may be designated by slow forward or slow reverse. In this manner, the deposition storage is set and cleared only through the raising motion at the bath itself, when driving past other stationary positions.

The operational mode of the switching arrangement may be seen from FIG. 4. With switching algebra, the applicable principle may be illustrated:

Storage SP1 in use=(SPl)=(STlA +ST1B) (S) (FV-i-FR) -Down Storage SP2 in use: (SP2) :(STZA +ST2B) (S) -FV+FR) 'Down Sorage SP1 vacant: (SP1)=(ST1A +ST1B) (H) '(FV+FR) -Up where represents the logical AND, and represents the logical OR.

Storage SP1 indicates vacant when the positional switch ST1 is set, while the raising command is transmitted, as is the driving command for up forward-:FV, or reverse=FR. In the latter case, the carriage has lifted the material carrier out of this bath, and has left therewith this location. In the first case, it has placed a material carrier at this location.

The starting lines serve the purpose of setting the deposition storage to its initial state in accordance with the desired program. This corresponds to the deposition state of the arrangement with material carriers.

In FIG. 5 a plating arrangement is illustrated schematically. The deposition locations and the plating baths are designated with the symbols Bl-B The positional switches are designated by the symbols ST1- The arrangement in accordance with the present invention has had particular advantages. Thus, the information of the deposition state can also be used for controlling the arrangement itself. For example, the loading of a multi-cell bath can be accomplished as a function of the actual or simulated deposition state. Similarly, other controlling processes can also be derived from this deposition information as, for example, diode switching, processing times, passage of individual baths, limiting the driving region, automatic reverse or return to the initial position, and many other functions.

Another advantage is that all circuit elements which sense the bath deposition on the transport or material carriers, are omitted.

A number of circuits or circuit elements may also be omitted on the plating baths themselves. Accordingly these are free of sensing devices and associated installations. The deposition information for the baths or deposition locations may be processed. In accordance with this principle, for automatic as well as for manual operation. In addition, the information can be stored throughout the deposition, so that it can be retained even upon failure of the control voltage.

The arrangement in accordance with the present invention also permits independent storage of the deposition state, when the applicable bath or deposition location has more than one transport carriage coming thereto.

What is claimed is:

1. An arrangement for controlling the operation and work cycle of plating baths comprising, in combination, plating means in said plating baths; material dispatching means; transport means with logic circuit means for transporting material means; deposition stations with logic circuit means; central control means with logic circuit means interconnected with said logic circuit means of said transport means and said deposition stations; and storage means in said central control means for storing work cycle information of each of said deposition stations, whereby said transport means carries varying material means at varying time intervals from said material dispatching means for varying plating conditions in accordance with predetermined requirements.

2. The arrangement as defined in claim 1 wherein each deposition station is associated with a storage means in said central control means.

3. The arrangement as defined in claim 2 wherein said storage means has a plurality of inputs.

4. The arrangement as defined in claim 3 wherein one of said inputs is connected to said transport means, the region of motion of said transport means encompassing the deposition station associated with said storage means.

5. The arrangement as defined in claim 1 including switching means on said transport means.

6. The arrangement as defined in claim 1 including 7. The arrangement as defined in claim 1 including raising storage means connected to said transport means.

References Cited UNITED STATES PATENTS 2,921,008 1/1960 Hauck et a1. 204-203 3,455,809 7/1969 Geilert 204-225 X 3,094,475 6/1963 Jackson et al. 204202 10 JOHN H. MACK, Primary Examiner D. R. VALENTINE, Assistant Examiner U.S. Cl. X.R.

lowering storage means connected to said transport means. 15 204225 

